Caption: MODEL RELEASED. Gel electrophoresis. Oncologist using a pipette to transfer proteins from a vial to a gel electrophoresis unit during cancer research. Gel electrophoresis is used to analyse the protein composition of cells and tissues. The extracted proteins are placed into a gel, which then has an electrical current passed through it that separates the proteins based on their size and charge. This technique can also be used to analyse the genetic makeup of cells and tissues. Photographed in the Division of Molecular Medicine at Dundee University in Dundee, Scotland.